(-)-.beta.-D-Aristeromycin (1R,2S,3R,5R)-3-(6-Amino-9H-purin-9-yl)-5-(hydroxymethyl)-1,2-cyclopentanediol .beta.-D-Carbocyclic adenosine 19186-33-5 AIDS-114231 AIDS114231 AVS-12219 Aristeromycin Cycloadenosine NSC103526